Revert of Remove EnableThreadedCompositing from the browser.

content/browser/gpu/compositor_util.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_GPU_COMPOSITOR_UTIL_H_
 #define CONTENT_BROWSER_GPU_COMPOSITOR_UTIL_H_
 
 #include "base/values.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 // Note: When adding a function here, please make sure the logic is not
 // duplicated in the renderer.
 
 // Returns true if the virtual viewport model of pinch-to-zoom is on (via
 // flags, or platform default).
 CONTENT_EXPORT bool IsPinchVirtualViewportEnabled();
 
+// Returns true if the threaded compositor is on (via flags or field trial).
+CONTENT_EXPORT bool IsThreadedCompositingEnabled();
+
 // Returns true if delegated-renderer is on (via flags, or platform default).
 CONTENT_EXPORT bool IsDelegatedRendererEnabled();
 
 // Returns true if impl-side painting is on (via flags, or platform default)
 // for the renderer.
 CONTENT_EXPORT bool IsImplSidePaintingEnabled();
 
 // Returns true if gpu rasterization is on (via flags) for the renderer.
 CONTENT_EXPORT bool IsGpuRasterizationEnabled();
 
 // Returns true if force-gpu-rasterization is on (via flags) for the renderer.
 CONTENT_EXPORT bool IsForceGpuRasterizationEnabled();
 
 CONTENT_EXPORT base::Value* GetFeatureStatus();
 CONTENT_EXPORT base::Value* GetProblems();
 CONTENT_EXPORT base::Value* GetDriverBugWorkarounds();
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_COMPOSITOR_UTIL_H_